Flotation of manganese ores



Sept. 17, F. WEED FLOTATION OF MANGANESE ORES Filed Aug. 26, 1933 ,Pol/GHEKYl/w INVENTOR flora MED.

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ATTORN EYJ Patented Sept. 17, 1935 UNITED STATES PATENT OFFICE 2,014,401 FLo'rATIoN oF MANGANESE omis Floyd Weed, Jefferson City, Tenn. Application August ze, 193s, serial No. 686,981

s claims. (ci. 209-166) This invention relates to a process for the concentration of oxide ores by flotation. It more specifically relates to the concentration of manganese oxide ores by flotation.

It is known that certain oils and fattyacids can be made to develop a marked selectivity for oxide minerals over the gangue minerals associated with them and that the oxide minerals can be separated from the gangue minerals by using admixtures of these certain oils and fatty acids as flotation reagents. Heretofore the processes employing these oils and vfatty acids have been characterized by the difficulty with which the reagents are admixed with and dispersed through the pulp and thereby brought in contact with the ore particles, and by the large amounts of such reagents that are required. Heretofore these oils and fatty acids, which are very slightly soluble in water, have been incorporated in the pulp and brought in contact with the ore particles by mechanical mixing means, using a pulp containing 75% solids or by dissolving the oils or fatty acids in a suitable solvent or b y converting the oils or fatty acids to soaps by the addition of an alkali thereto in the case of soap forming fatty acids or oils containing a substantial proportion of them.

In accordance with the inventions of my copending applications Serial No. 637,527, No. 637,- 528 and No. 637,542 filed October 12, 1932, I have found that by first colloidally dispersing these reagents in a suitable water soluble or miscible medium and thereafter adding the colloidally dispersed reagent to the flotation pulp, the separation of oxide minerals is greatly facilitated and that the consumption of reagent is greatly reduced.

In effecting the flotation of oxide minerals, in order to make satisfactory recoveries and satisfactory grades, it is essential in most cases to use a combination of reagents, a typical combination being one such as oleic acid and kerosene oil. Neither reagent by itself will function satisfactorily to secure the results which are desired. They both have their functions to fulfill. In the separation of manganese ores oleic acid being the collecting agent, 'and kerosene oil the selecting or modifying agent, the colloidal dispersion of 1 each of these reagents or of both together pro-` duces the economic results which are desired. If the oleic acid is not colloidally dispersed and the kerosene oil is colloidally dispersed, inferior results would be secured over that obtainable when both are colloidally dispersed and the same is true if the oleic acid is colloidally dispersed and the kerosene oil is not so dispersed. Furthermore, unless both are colloidally dispersed, the reagents cannot be manipulated so as to secure full effectiveness of the frothing, collecting and modifying properties. l'Either reagent if addqi non-colloidally dispersed tends' to form globules `which may float on the top of the water or if they are mixed in the pulp mass by agitation are present in too large globules or units to make effective contactvwith as large a number of mineral particles as when they are colloidally dispersed.

The result is that the addition of reagents that are not colloidally dispersed tends first to greatly increase the amount of reagents needed and secondly to render far more difficult the securing of concentrates with desired grade.

It is the object of this invention to provide reagents that are easily dispersed through the flotation pulp .and that still retain their original characteristics in regard to selectivity, and are selective with respect to the recovery'of manganese minerals. It is further the object to provide reagents that can be more easily dispersed and brought in contact with the mineral particles and thereby be used in decreased amounts. Other objects and advantages will be apparent.

In accordance with the objects of the present invention I have discovered that the principle dif ficulty attending the practice of froth otation on non-sulfide ores, minerals and the like and the reason for theexcessive use of reagents lies in obtaining the proper dispersion within the flotation pulp'of the particular .reagents having the desired selective aflinity for the metalliferous values of the ore.

-It was found that by adding the reagents as colloidal dispersions that they retained their characteristics in regard to selectivity to the mineral particles, that they were dispersed readily through the pulp and that the amounts of reagent required were greatly reduced. Further, the reagents could be added at any point in the circuit desired and at any pulp density, thereby facilitating the flotation practice.

Colloidal dispersions of the preferred flotation reagents are preferably made using water containing a small amount of a soap compound formed with oleic acid and triethanolamine. To this soap solution the oils or fatty acids serving as iiotation reagents are added and the mixture agitated until the desired dispersion of the reagents is obtained. Instead of the oleic acid-triethanolamine soap compound, other soap compounds such as sodium oleate, cottonseed foots soap, stearate soaps and the like may be used. The dispersions of the reagents employed need not be permanently stable and may therefore be made with a minimum amount of soap compound and, accordingly, most oils and fatty acids useful as reagents about 1% of soap in the-water solution is sufficient. Olei'c acid, for example, reacts with triethanolamine in the ratio of 2.7 parts oleic acid to 1 part triethanolamine to form a soap, and 1% (byweight) of this soap compound may be added -to a volume oi water, or the two cominsite,

amounts to react and form in solution about this amount of soap compound, as may be desired.-

The chief manganese minerals present in manganese ores are pyrolusite, psilomelane, manganite and wad, all manganese oxides of varying Purity and varying degrees of lrvdration. 'Ihese oxides of manganese are all susceptible to notation. It is found however that depending upon the speciiic ore, available water and many other factors the basic otation process of the present invention must be varied somewhat. As a specific em' bodiment of the practice o1' the present invention, I will describe the same as it has been applied to a single type of ore, and will thereafter disclose the factors which influence or modify the practice of the same.

e As a specific embodiment I will describe the practice of the present invention using manganese ores known to the trade as Cuban mansanese ore, the name being derived from their place of origin'. Cuban manganese ores contain pyropsilomelane, manganite, hausmanite, braunite and wad, all manganese oxides of varying purity and with varying degrees of hydration. The gangue minerals are largely silicates, feldspars and volcanics.

In conjunction with the following description of the present invention reference should be made to the accompanying drawing wherein a single figure, a flow sheet diagram of the flotation process grinding the ore to such a size`as will substantially free the manganese minerals from the gangue; (2) the preparation of a pulp by the addition of water,the addition and dispersion of reagents which have the desired selectivity for the manganese minerals; '(3) flotation; (4) dewatering the concentrate; and (5) disposal of the tailings.

The manganese ore is ground to 6% lplus 65 mesh and a pulp made up containing approximately 33% solids. The water used should preferably be substantially free from soap consuming impurities, such as chlorides, sulfates and organic acids-distilled water if available in economic quantities, or natural waters treated with well known water softening agents are preferred. I'his does not mean however that hard waters or that waters containing soap consuming impurities cannot be used. With such waters an`intelligent selection of soap compound and of quantities of flotation reagents added must be employed.

A colloidal dispersion of oleic acid and kerosene oil in water, formed with the minimum amount of saponiflcation is preferably used as a flotation reagent. 'I'iethanolamine is also preferably used as the saponifying agent and since the colloidal dispersion of the oleic acid and kerosene need not be permanently stable the minimum amount of the triethanolamine-oleic acid soap compound may be employed. It is estimated that this minimum is approximately 1% of the total oleic acid. Other soap compounds may be used, the preference being determined by such factors as alkalinity, water impurities and the particular characteristics of the ore, but we have found that colloidal dispersions made by using triethanolamine soap compounds are of wider apa,o14,4o7

plication and produce more uniform results than do other soap compounds.

Amounts of the colloidal dispersion suiilcient to contain 5 pounds o'f oleic acid and 0.3 pounds of kerosene per long dry ton of ore are used for the through the rougher flotation cells. The rougher flotation is made with a pulp density of approximately 33% solids.l The rougher tailing is a final tailing and is disposed of. The rougher concentrate is cleaned by refloating in a manner similar to rougher flotation but at a lower pulp density. The cleaner concentrate is dewatered in some suitable manner and the cleaner tailing is returned to the rougher circuit. The preferable way of treating the cleaner tailing is to classify them in some manner, returning the oversize to the grinding circuit and desliming the undersize before returning to the rougher circuit. The slimes are cumulative in the circuit and are detrimental to the notation when present in excess amounts. Theymay be treated in a separate circuit or discarded as a tailing. The following test illustrates the reagent consumption and extraction.

Reagents used per to n Extraction Comte 5 pounds oleic acid 86. 8% 42. 0% Mn 0.3 pound kerosene 0.05 pound triethanolamine Illustrating the adaptability of colloidal dispersions to dilute pulps produced either through the removal of contained minerals, or return of products within the mill circuit for retreatment, and for the purpose of showing the continuing control of flotation during successive steps of the operation, the following procedure was followed which in respect to grinding and reagents is the same as the'preceding test but varies in respect to the pulp densities.

'I'he ore is ground to 6% plus 65 mesh and a pulp of any convenient density made up using water free from soap consuming impurities, distilled water being preferable.

The flotation reagents used are the same as those in the preceding specific embodiment, namely, a colloidal dispersion of oleic acid and kerosene in water containing a triethanolamine soap compound. Part oi' this reagent isadded to the pulp and conditioned before notation and the remainder is added as flotation proceeds in the diluted pulp.

The conditioned pulp is diluted to contain 3 to 10% solids and a rougher flotation made producing a rougher concentrate and a final tailing. The final tailing is dewatered and a portion of the water returned to the circuit, this vamount depending on the degree to which the slimes are removed by thickening. The rougher concentrate made in dilute pul'p containsless entrained gangue and slime than when made in the usual 30 to 50% pulp densities. A much lighter froth is formed. The rougher concentrate is cleaned by refloating and the cleaner tails thickened and returned to the rougher circuit after classifying, regrindlng the oversize and desliming. Any portion of the water from the cleaner tailing may be returned to the cleaner circuit as far as diluting the rougher circuit is concerned and depending only on the presence of deleterious ore constituents that may accumulate and build up within the circuit with unfavorable results. Tlie cleaner concentrate is dewatered in some suitable manner. The following example illustrates the reagent consumption, recoveries and concentrate grade obtained with dilute pulp flotation.

5.0 0.3 pound kerosene 0.05 pound triethanolamine The flow sheet diagram of the drawing disr closes the flotation process of the present invention as it may be used with either a dilute or concentrated pulp density.

From the above description of the two applications of the present invention it is apparent that many modifications and adaptations thereof may be made without departing essentially from the nature and scope as may be covered in the appended claims.

One of the advantages of the present invention resides in the recovery of slimes. Ordinarily the crushing and grinding operations to free the manganese minerals from the gangue forms a large percentage of manganese slimes and nes and heretofore in the art processes for recovering these minerals have consisted in the main of mechanical operations, commonly called gravity concentration, wherein this portion of the manganese minerals was lost and only the larger lumps and grains recovered. By the flotation process of the present invention a large portion of the slimes and fines can be recovered.

In prior art attempts to utilize the flotation process for the recovery of manganese minerals, the flotation reagents commonly used have consistcd of soaps of some type, such as cottonseed foots soap or fish oil soap and mineral oils such as fuel oil. These reagents have heretofore been mechanically incorporated Within the flotation pulp. As a result of this mode of incorporation great difficulty has been experienced in obtaining satisfactory recoveries except through the use of relatively large quantitiesof such reagents. Such large quantities are still more diflcultly admixed uniformly and economically into and throughout the pulp. By the practice of the present invention use of large quantities of reagents is eliminated as the colloidally dispersed reagents are easily and readily incorporated into and dispersed throughout the pulp. Y

The following examples will illustrate this feature:-

The prior art practice has found it necessary to use a pulp density approximating 50% solids for satisfactory recovery as theincorporation of these large quantities of reagents into the pulp has not otherwise been successful. In the flotation of oxide minerals and in particular mangancse minerals, by prior art methods the usual high percentage of mineralcontent of such ores results in a rapid decrease in pulp density as soon as flotation starts and due to this dilution and to the method of incorporating the reagent as heretofore used. any further or supplementary addition of the flotation reagent cannot be made successfully and as a result thereof, a. continuing control cannot be had. By the practice of the present invention the colloidally dispersed reagents can be introduced at any point in the flotation process with any pulp density, and with continuing and predictable results.

The following tests illustrate the benefits of progressive addition of the colloidally dispersed reagents:-

Concentrate Extraction grade Reagents used per ton IV Reagents colloidally dispersed and progressively added as re Gnlred.

18 lbs. cottonseed loots soap. 22 lbs. gas oil.

Furthermore, the necessity of using large quantities of flotation reagents and incorporating them with the dense pulps in advance of flotation has resulted in the very rapid forming of a heavy mat which would mechanically entrain gangue particles and slime, increasing the -dfliculty of cleaning the rougher froth to a commercial grade, and removing from the pulp a quantity of the reagents in excess of that needed to float the mineral, thereby producing a froth of objectional characteristics and difficult to handle and making an uneccnomical use of such reagents. In the practice of the present invention the reagents can be applied progressively, as shown in tests III and IV (above), to avoid the initial rapid and excessive formation of froth and continue it more uniformly throughout the machine. The benets, both to recovery and concentrate grade, of the progressive addition of colloidally dispersed reagents are further illustrated in the following tests.

While it has been found in general that diluteness of pulp has resulted in increased consumption of reagents, in the practice of the present invention the initial rapid floating of the mineral and the attendant loss of reagents is avoided and more than compensates for the theoretical additional quantity that might be needed through the successive addition of reagents to diluter pulp. This is illustrated by the tests V and VI in the preceding paragaph.

In the speciflc embodiment of the practice of the present invention I have indicated that it is preferable to utilize water that is substantiallyl the following examples show the amounts of reagents needed using natural and impure water and with pure Water (using prior art practice) as compared with the economy and beneficial results obtained by using the colloidally dispersed reagents of the present invention.

Concentrate Extraction grade Reagents used per ton VII. Mi'lil waer. Notn-colloldally isperse rangen s 24lbs. cottonseed foots soap 89' 0% 28 lbs. gas oil Distilled water. Nonco1loid ally dispersed reagents sa 0% VIII.

l5 lbs. cottonseed loots soap 38' 5% Mn 18 lbs. gas oil Distilled water. Colloidally dispersed reagents progressively added as required 9i. 5%

42. 5% Mn l5 lbs. cottonseed foots soap.- 18 lbs. gas oil From this test it will be seen that when mill water is used in accordance with prior art practice the reagent consumption is relatively high. When distilled water is used under similar conditions the reagent consumption is relatively low. And that when distilled water is used in accordance with the present invention a still further improvement is obtained, namely, an increase in the per cent extraction and grade of product.

The present invention therefore is subject to many modifications and departures from the speciilc embodiment herein disclosed and all such are contemplated as may fall within the scope of the accompanying claims.

What I claim is:

l. In the concentration of manganese ores by flotation the method which comprises forming a flotation pulp of desired density, adding thereto a proportion of oleic acid and kerosene colloidally dispersed in water containing a proportion of triethanolamine, and thereafter subjecting the pulp to froth flotation.

2. 'Ihe method of concentrating manganese ores by flotation which comprises crushing and grinding the manganese ore to a size adapted to substantially free the manganese minerals from the gangue, forming a flotation pulp of desired density by the addition of water thereto, incorporating therewith a proportion of a mixture of oleic acid and kerosene colloidally dispersed in water containing a proportion of triethanolamine soap compound, subjecting the pulp to a rougher froth flotation and then recovering, cleaning and dewatering the floated concentrates.

3. Themethod of concentrating manganese ores by flotation which comprises crushing and grinding the manganese ore to a size adapted to substantially free the manganese minerals from thel gangue, forming a flotation pulp of desired density bythe addition of water thereto, incorporating therewith a proportion of a flotation reagent comprised of oleic acid and kerosene colloidally dispersed in water containing a proportion of triethanolamine, subjecting the pulp to a rougher froth flotation and then recovering, cleaning and dewatering the floated concentrates.

4. The method of concentrating manganese ores by flotation which comprises crushing and grinding the manganese ore to a size adapted to substantially free the manganese minerals from the gangue, forming a flotation pulp of desired density by the addition of water thereto, incorporating therewith a proportion of a flotation reagent comprised of a colloidal dispersion of oleic acid and kerosene in water containing a proportion of an alkyl-amine soap compound, subjecting the pulp to a rougher flotation and then recovering, cleaning and dewatering the floated concentrates.

5. The method of concentrating manganese ores by flotation which comprises crushing and grinding the manganese ore to a size adapted to substantially free the manganese minerals from the gangue, forming a flotation pulp of desired density by the addition of water thereto, incorporating therewith a proportion of a flotation reagent comprised of a fatty acid and a mineral oil colloidally dispersed in an aqueous solution of an ethanolamine soap compound, the said oil having the desired selectivity for the manganese minerals of the pulp, subjecting the pulp to a rougher froth otation and then recovering, cleaning and dewatering the floated concentrates.

6. The method of concentrating manganese ores by flotation which comprises crushing and 40 grinding the manganese ore to a size adapted to substantially free the manganese minerals from the gangue, forming a flotation pulp of desired density by the additionA of water thereto, incorporating therewith a proportion of a. flotation reagent comprised of a fatty acid and a mineral oil admixed in the desired proportions and having the desired selectivity for the manganese minerals of the pulp, said reagent being colloidally dispersed in a. water solution of an alkylamine soap compound, subjecting the pulp to a rougher froth flotation and then recovering, cleaning and dewatering the'floated concentrates.

7. The method of concentrating manganese ores by flotation which comprises crushing and substantially free the manganese minerals from the gangue, forming a flotation pulp of desired density by the addition of water thereto, incorporating therewith a proportion of a flotation reagent comprised of a fatty acid and a minerai oil admixed in the desired proportions and having the desired selectivity for the manganese minerals of the pulp, said reagent being colloidally dispersed in a water solution of a triethanolamine soap compound, subjecting the pulp to a rougher froth flotation and then recovering, cleaning and dewatering the floated concentrates. 8. A reagent for use in the concentration of manganese ores by flotation which comprises. an admixture of oleic acid and kerosene colloidally dispersed in water containing a proportion of a triethanolamine soap compound.

FLOYD WEED. 

